Tyrannosaurus rex with a huge body, sharp claws and dagger-like teeth he didn’t rely on looks to kill. But research shows that its eyes can trigger its bone-crushing bite.
The study suggested that T rex’s keyhole-shaped eye sockets may have helped spread stress across the skull when cutting down a fearful predator.
“They had really special eye socket shapes that helped them cope with high bite forces,” said Dr Stephan Lautenschlager, a vertebrate paleontologist at the University of Birmingham and author of the study.
But, he added, the benefit of skull stability may come at a cost, noting that T rex had relatively small eyes for its skull size.
Although Lautenschlager said this does not necessarily mean that the T rex had poor vision, he did say that the large eyes are associated with sharper vision.
“There is some trade-off between better vision, bigger eyes, but higher stresses on the skull. [a circular eye socket],” I said.
Write in a journal Biology of communicationLautenschlager analyzed the shape of the eye socket, or orbit, of 410 species that lived between 252 and 66 million years ago, including the ancestors of dinosaurs, pterosaurs and crocodiles.
His results show that while most species have circular eye sockets, some have keyhole or figure-eight orbits.
“About two-thirds or three-quarters have a typical circular orbit, and the rest go beyond that and do something more extreme or more elegant,” Lautenschlager said.
Lautenschlager notes that keyhole or figure-of-eight orbits were generally found among carnivores with large skulls, particularly large carnivorous theropod dinosaurs such as Tyrannosaurus rex..
“Within theropods, there are several groups that changed their diet and adapted to a plant- or herbivorous diet. And they still have circular orbits,” Lautenschlager said. “Voice [orbit shape is] closely related to diet and size.”
Using a series of computer models to examine the consequences of different eye socket shapes, Lautenschlager found that a round orbit was associated with greater deformation of the bones around the eye socket during biting, and was keyhole or figure-eight shaped. the orbits helped to distribute the stresses throughout the skull, so they were not concentrated at one point.
The study also suggests that rounded orbits may limit the space for the jaw muscles and thus their size, which Lautenschlager notes may affect overall bite force.
Lautenschlager said it’s likely that non-circular eye sockets and high bite forces evolved in parallel.
“It’s interesting that you see juvenile T rex still have perfectly circular or nearly circular orbits because they probably didn’t generate as high bite forces or had a slightly different diet or a different prey repertoire.” said Lautenschlager.
Professor Steve Brusatte, a paleontologist and T rex expert at the University of Edinburgh who was not involved in the study, welcomed the research.
“When you look at the eyes of a T rex skull, the eye socket looks a bit funny, like a keyhole. “It looks small for an animal with a head the size of a bathtub,” he said.
“This groundbreaking new study shows that the eyes of T rex were not only shaped by the need for sharp vision, but also by the need for a powerful bite,” said Brusatte.
“As strange as it may seem, T rex’s eyes helped make it one of the strongest bites in Earth’s history.”
